Transmission cooler maintenance

[Tomcat]

We did an engine oil and transaxle fluid change on my Buddy's 2006 GT. I then noticed that he has an additional external transmission cooler on the passenger side. Before I saw this we drained and refilled the transaxle with the correct fluid and it took almost exactly 4 quarts (which is also all I had ordered)
My questions:
1) How much fluid is "trapped" in the cooler/lines and how should I drain that? And how do I refill the cooler?
2) Although not ideal, I did not measure how much "old" fluid came out of the transaxle drain plug. When it stopped draining I refilled (again about 4 quarts) and the level was up to the fill plug...so I assumed that the plumbing does not allow the cooler to drain out the bottom drain plug (as it "seemed" to stop draining after a reasonable time/amount (again unmeasured)).
3) The "old" fluid looked pretty good so although my new fluid MIGHT be diluted with some of the old fluid, my biggest concern is that I might have drained some of the additional fluid from the lines/cooler and the system is not full. How can I check?
Thanks,
Tom

 

[nota4re]

How much oil is in the transaxle cooler system likely depends on which cooler kit is used - although they're probably pretty close. I can tell you that our transaxle cooler kit will increase overall capacity by .78 quarts. We have always advocated that customers add that additional .78 at the end of the installation - and we included a quart with all of our kits.

The Ford Racing transaxle cooler has a slightly smaller heat exchanger that the Setrab unit in our kit. However, their lines to and from are slightly larger so it problem nets out to about the same. Interestingly, in Ford Racing's official instructions they never advocated to add any additional oil.

There's another difference between the two kits as well. We chose to fill the heat exchanger from the bottom and the return out the top. The Ford Racing kit circulates the fluid from the top to the bottom.

In changing the transaxle fluid, you will not get the fluid out from the cooler. With or without a cooler, you will drain out ~3.9 quarts and that's what you will add back in. If you are compelled to also drain the ~.75 quarts, you will need to remove the bottom fitting from the heat exchanger.... and that could quickly get quite messy.

 

[Tomcat]

Hey Kendall, thanks for the response this is Doctor David's car and it's your Setrab unit. What I'm understanding is doing a 3.9 quart refill through the standard drain plug is acceptable even with additional trans cooler.

 

[nota4re]

Hey Kendall, thanks for the response this is Doctor David's car and it's your Setrab unit. What I'm understanding is doing a 3.9 quart refill through the standard drain plug is acceptable even with additional trans cooler.

Yes, exactly. Just drain and re-fill until it drools out the fill hole. Also, make sure you remove and clean BOTH drain plugs. The driver's side plug will have a fine screen that should be cleaned and the passenger's side plug will have nice sized fuzz-ball on the magnetic tip that should be cleaned. Finally, never use anything but the Motorcraft GT-spec transaxle fluid... which in cost per ounce is recently giving gold a run for the money!

 

[Tomcat]

Yes, exactly. Just drain and re-fill until it drools out the fill hole. Also, make sure you remove and clean BOTH drain plugs. The driver's side plug will have a fine screen that should be cleaned and the passenger's side plug will have nice sized fuzz-ball on the magnetic tip that should be cleaned. Finally, never use anything but the Motorcraft GT-spec transaxle fluid... which in cost per ounce is recently giving gold a run for the money!

Using all Motorcraft fluids and yes it's gold. Thanks again for your technical support

 

[Tomcat]

...and the passenger's side plug will have nice sized fuzz-ball on the magnetic tip that should be cleaned. ...

I do not see this referenced in the service manual...but I knew/know this from experience.

 

[Art138]

Yes, exactly. Just drain and re-fill until it drools out the fill hole. Also, make sure you remove and clean BOTH drain plugs. The driver's side plug will have a fine screen that should be cleaned and the passenger's side plug will have nice sized fuzz-ball on the magnetic tip that should be cleaned. Finally, never use anything but the Motorcraft GT-spec transaxle fluid... which in cost per ounce is recently giving gold a run for the money!

Here is a pic of the drain plug screen:

 

[HOOKED ON GT]

Kendall if you disconnect the top line on the heat exchanger whilst the bottom drain plug is out won't that "relax" the system and allow the exchanger oil to flow to bottom/out?....... no mess this way
Can you refill the 4.8 quarts through the top exchanger line (could be pretty slow) or do as per Fords 4 quarts refill at the normal fill location and do your top up volume from the exchanger?

Stuart

 

[nota4re]

Hi Stuart,

The top line to our (Setrab) heat exchanger is connect to the return "in" port on the transaxle. This is why you can add oil into the line and it will flow into the cooler. The bottom line of the heat exchanger is connected to the "out" port of the transaxle. In short, our kit pumps to the bottom of the cooler up and out the top and back into the transaxle. We did it this way intentionally. By contrast, the Ford Racing kit flows the fluid top to bottom through the heat exchanger.

Assuming you have our (Cool Tech) transaxle cooler, even if you disconnect the top line, the fluid in the cooler will not drain back in through the pump (in our experience).

 

[2112]

So I take it that means the Ford cooler will drain back into the case when the car is sitting?

 

[HOOKED ON GT]

I guess best bet is replace the volume out with the same new amount back in.

Thanks for the info

 

[nota4re]

So I take it that means the Ford cooler will drain back into the case when the car is sitting?

I would assume so. Note that the Ford Racing installation instructions do not advocate adding additional oil at time of install.

 

[GT@50]

Is the pump driven by the input or output? ZF6 is driven any time the engine is running(foot off clutch). A Gallardo trans I did was driven off the pinion shaft(IIRC) and only driven when wheels are turning. Either way, drain trans and pull bottom cooler line to drain cooler. Reattach and add 5 quarts to speedo hole. Put speedo back in, don't cut O ring. Fire engine, let wheels rotate for a minute(only necessary if pump is driven by output), shut it off, remove fill plug and let drain to proper level(should be done in a few seconds)

 

[GT@50]

I would assume so. Note that the Ford Racing installation instructions do not advocate adding additional oil at time of install.

There's a science project. Run trans like a dry sump(well, not quite) being .8 quarts low vs with an extra .8 quarts in the system. I'll take the extra fluid but I'd bet both ways are just fine.

 

[HOOKED ON GT]

Yes, exactly. Just drain and re-fill until it drools out the fill hole. Also, make sure you remove and clean BOTH drain plugs. The driver's side plug will have a fine screen that should be cleaned and the passenger's side plug will have nice sized fuzz-ball on the magnetic tip that should be cleaned. Finally, never use anything but the Motorcraft GT-spec transaxle fluid... which in cost per ounce is recently giving gold a run for the money!

Hi Kendal
I just got the 3:90 rear changed out and had Jason Heffner add the OE rear spec trans oil, but an email from my HCF contact said that his installer recommended Amsoil.
Ive not asked them or Jason on their thoughts v's each option,
What do you think?

Stuart

 

[nota4re]

I wouldn't use ANYTHING but the factory fluid in the transaxle.

 

[PeteK]

If you consider using anything else, start doing regular oil analysis. I’d suggest a sample at 2000 miles, then 5000 miles, then 10,000 miles. If there’s any increase in metals, change back to the OE stuff. If there’s no increase in metals, then sample and change at 30,000 miles.

 

[GT101]

Does anyone know a source for the OE trans fluid? - Ford seem to have none and no ETA for it.

 

[fjpikul]

David, there was a long thread about this a few months ago.. Seems like Rock Auto had some.

 

[GT101]

Thanks Frank - unfortunately Rockauto are out too.
My guy has spoken to other dealers who've had orders in for over six months and no dates or ETA for supply.